diff --git a/bundle/schema/schema.go b/bundle/schema/schema.go
index 47b84aabd..84c3f9923 100644
--- a/bundle/schema/schema.go
+++ b/bundle/schema/schema.go
@@ -169,6 +169,10 @@ func toSchema(golangType reflect.Type, docs *Docs, tracker *tracker) (*jsonschem
 	jsonSchema := &jsonschema.Schema{Type: rootJavascriptType}
 
 	// Variables can be set as the value at any node in the configuration tree.
+
+	// At every node in the configuration tree we allow string values, provided
+	// they are a variable reference. Any node (scalar, object or array) can be
+	// set as a variable reference.
 	if rootJavascriptType != jsonschema.StringType {
 		jsonSchema = &jsonschema.Schema{
 			AnyOf: []*jsonschema.Schema{